The present invention relates to an exposure apparatus for printing the image of a negative film on a photosensitive plate with the film superposed on the plate by exposing the plate to the image with a light source disposed above the film.
Exposure apparatus of this type heretofore known are divided into two general types:
(1) Those in which a fixed baseboard having a plate receiving surface in a horizontal or substantially horizontal position for holding a photosensitive plate in intimate contact therewith is in alignment with a path of transport of the plate for feeding the plate to the baseboard and delivering the plate from the baseboard after exposure. The baseboard is movable transversely of the direction of transport of the plate to a position in the path or alternatively to a position below the main body of the apparatus having an exposure light source disposed above the path on one side thereof. PA0 (2) Those in which the above-mentioned fixed baseboard and the main body of the exposure apparatus are always fixedly provided in the path of transport of photosensitive plates in alignment therewith, and a negative film retained in position in the form of a roll is paid off and superposed on a photosensitive plate fed to the baseboard.
The exposure apparatus of these two types have the following advantages and drawbacks.
With the apparatus of the type (1), the negative film need not be rolled up but is usable in its original planar state and is therefore very easy to set or reset on the baseboard. The negative film, which is not curly, can be superposed on the photosensitive plate in highly intimate contact therewith and enables a squeegee roll to effectively remove air from between the film and the plate. Despite these advantages, the apparatus have the drawback of necessitating an increased floor space for installation in its entirety because the main body including the light source is located on one side of the path of transport as projected therefrom.
Although the apparatus of the type (2) have the advantage of assuring a reduction in the floor space needed with the baseboard and the main body disposed fixedly in the path of transport at all times, the negative film, which is curly, fails to fit to the photosensitive plate intimately and is very likely to warp, permitting some air to remain again between the film and the plate even after air has been pressed out and removed from therebetween and consequently giving a print with an uneven density or a blurred image.